The present invention relates to a take up adjuster for thrust washer wear and in particular relates to a set of upper and lower solid steel wedges placed between thrust washers and a swivel mount and constructed so that maintenance personnel can quickly and easily take up the clearance between a swivel bracket and thrust washers supporting the bracket by tightening a pair of bolts which draws the lower wedges together thereby raising the upper wedge and increasing the thickness of the adjuster assembly.
In heavy machinery such as draglines, cable sheaves are mounted in swivel brackets which are pinned to a swivel mount on the structure at various locations. The swivel bracket wears on thrush washers located on the pin at the top and bottom of the swivel bracket. As the washers wear due to the swiveling of the bracket, the clearance between the thrust washers and the swivel bracket opens or increases thus allowing the swivel assembly to jack up and down inducing impact loads against the mounting structure and causing heavy vibration throughout the machine. Inasmuch as great loads are applied to these sheaves, tremendous forces are applied to the swivel assembly thus causing damage to the equipment as the clearance between the bracket and the thrust washers increase due to wear. To correct this problem, the machine must be idled while the pin on which the swivel bracket is mounted is removed and shims added to form a shim pack and collar assembly on the pin to take up the space between the swivel bracket and the thrust washer caused by wear thus preventing the up and down movement of the swivel assembly which creates the damage to the equipment. Obviously this requires not only the idling of the machine but additional time and expense of the maintenance personnel to remove the pin, insert the shim pack and collar assembly of the proper dimensions in the space where the wear has taken place and replace the pin. Further, an assortment of various sizes of shims must be kept in stock so that the space caused by wear can be accurately filled.
The proposed invention eliminates these problems by eliminating the shim pack assembly. A set of solid steel wedges are constructed so that maintenance personnel can quickly and easily take up the clearance at the swivel bracket simply by tightening a pair of bolts which draws a pair of lower wedges together thereby raising at least one upper wedge and increasing the thickness of the adjuster assembly until the space caused by wear has been eliminated. The adjuster utilizes a pair of lower wedge plates having bolts connecting them to pull them together and at least one upper wedge plate mounted about the pin and having wedge surfaces in contact with corresponding wedge surfaces of the lower wedge plate so that when the lower wedge plates are brought closer together, the upper wedge is raised
Thus no disassembly and reassembly of parts is required to make the adjustment as is needed with the present shim pack. Further, adjustment can be made quickly with only a wrench. There is also no need to stock extra parts such as shims as in the prior art. In addition, the adjuster indicates when the thrust washers must be replaced. In such case, the lower wedges come together when the limit is reached and can be adjusted no further. At that point, new thrust washers must be added. Also, a more accurate and complete adjustment can be achieved with the present invention since it is impossible to remove all clearance with the shims of the prior art since an infinite variety of shim thicknesses can not be maintained. There are fewer parts to the present invention and it can be made to retrofit existing machines with no other modifications.
Thus it is an object of the present invention to provide a take up adjuster for a swivel device mounted on a structure for swiveling on thrust washers about a pin wherein the adjusting body is positioned about the pin between at least one thrust washer and the mounting structure and comprising a first pair of wedge plates positioned on diametrically opposed sides of the pin and a second wedge positioned about the pin and having wedge surfaces complimentary to and in sliding engagement with the first pair of wedge plates so that when the first pair of wedge plates are forced closer to each other, the second wedge is raised upward to fill the space existing between the mounting structure and the swivel thrust washer.